"Two brothers and a cousin were killed when their motorcycle touched off an Improvised Explosive Device (IED) in a road in Shawal area of Nad Ali district late Thursday," provincial police spokesman Farid Ahmad Farhang told Xinhua.

The IED was emplaced by the Taliban insurgents in recent times in the province, 555 km south of capital Kabul, he said.

Notorious for growing poppy and militancy, Helmand has been branded as Taliban hotbed in southern part of the insurgency-hit country.

Taliban militants, who have been waging an insurgency of more than one decade, have often attacked Afghan and NATO-led forces with IEDs and roadside bombs but the lethal weapons also inflict casualties on civilians.

From Jan. 1 to Sept. 30 this year, more than 340 civilians have been killed and around 600 were wounded in IED explosions across the insurgency-hit country, according to figures released by the UN mission in the country in October.